The present invention relates to an optical information detecting device having a matrix array of integrated semiconductor elements that are operable in either a photoresponsive or photoemissive mode. The present invention is particularly adapted to improving the performance of optical interfaces, optical transmitters, and image detecting apparatus such as bar code scanners or readers, optical heads, and other optical scanners.
Information of various types may be encoded in graphical form as one or more barcodes, including linear barcodes, in which parallel bars of various widths and spacing may represent encoded information, and matrix (or “two-dimensional”) barcodes, in which encoded information may be represented by a two-dimensional pattern of shading (e.g., Quick Response (“QR”) codes). Barcodes may typically be configured to be machine-readable, in order to facilitate retrieval and decoding of the information they represent for various purposes. Mobile computing devices and related applications may sometimes provide the capability to capture and/or decode barcodes of various types. For example, a camera-equipped cellular phone may be utilized to capture an image of a barcode (e.g., a QR code) and an internal (and/or remote) application may be utilized to decode the information encoded therein.
Laser barcode scanners were invented several decades ago. The principle of these scanners is to use a laser beam to scan a barcode and then the laser barcode image will be reflected from the barcode to a point-type sensor (such as a photodiode or phototransistor). Then, the reflected laser barcode image is converted into electronic signals which will be decoded by a decoder into numbers and/or characters represented by the barcode.
The original laser light comes from a point-shape laser beam, and so in order to perform the scanning of a barcode, there are two ways: one is moving the laser light by a hand in a scanning light line as shown in FIG. 1; the other is moving the laser light by a mirror as shown in FIG. 2.
Heretofore, it is known that the light source of the barcode scanner is laser diode, the point type expanding light beam passes through a collimating lens and is transferred into a point type parallel light beam and then reaches a target barcode by reflecting the light beam using a mirror. The mirror rotates with a definite angle or vibrates to have the light “point” move from left to right (or from right to left) on the target barcode to scan the barcode, the scanned image is reflected back to a “point type” receiver (photodiode sensor, for example) to detect and decoded by the following electric components. The disadvantage of this design: i.e., to vibrate or rotate a mirror to send out the point type light source; the mirror might not be easy to be adjusted during manufacturing process, the mirror can be tilted or even disordered by collision.
As shown in FIG. 2, the light source structure includes a polygonal mirror 11 having a number of sides, each side of which is an independent mirror, so that the light emitted by laser diode 13 passes through a collimator 14 to be converted into parallel point-shape laser beam to one side of the polygonal mirror 11. Then, the parallel point-shape laser beam will be reflected to the barcode 2 and generate one laser point on barcode, and then the laser point image will be reflected back to the polygonal mirror 11. Thereafter, the reflected laser point image will be reflected again by polygonal mirror 11 and focused to a point-type sensor 15 by a light condensing lens. When the polygonal mirror 11 rotates, all sides of the polygonal mirror 11 will move and change the position and then the parallel point-shape laser beam will be reflected by the mirror at different angles, thereby enabling the parallel point-shape light beam to project on different positions of the barcode, and therefore causing the movement of the laser point. Due to the rapid rotation of the polygonal mirror 11, the reflected laser point will be moved rapidly, thereby producing the scanning effect.
Because of the rapid movement of the polygonal mirror 11 or moving the laser light by hand in a scanning light line as shown in FIG. 1, a linear scanning light will be formed to cover the whole barcode 2, so as to achieve the scanning operation.
The scanners requiring manual movement (See FIG. 1) occupy no more than one percent of the market. The scanners with the rotating mirror or the vibrating mirror (see FIG. 2) occupy the remainder of the laser barcode scanner market. However, the manufacturing cost for the rotating polygonal mirror or the vibrating mirror is expensive, the mirrors can be easily broken and are difficult to manufacture. Furthermore, the light source (13 in FIG. 2) and the sensor array (15 in FIG. 2) are typically disposed on separate circuit boards. That is, current optoelectronic devices used to sense motion or bar codes, for example, but not limited thereto, have separate chips for the light source, detector and processing electronics.
Therefore, it is desired to provide a light source without moving parts and reduce the number of circuit boards for an optical transceiver/optical information detecting apparatus, including a laser barcode scanner, which can obviate and mitigate the above-mentioned drawbacks.